[R] color ranges on a 2D plot

[Greg Snow]

You did not say what variable you want to be in the ranges to determine
the colors, but try any of these to see if they do what you want:

> x <- runif(100)
> y <- runif(100)
> z <- runif(100)
> plot(x,y, pch=16, col=ifelse( x < 0.5, 'blue','red'))
> plot(x,y, pch=16, col=ifelse( y < 0.5, 'blue','red'))
> plot(x,y, pch=16, col=ifelse( z < 0.5, 'blue','red'))
>
> library(TeachingDemos)
> y[1] <- 0.5
> plot(x,y, pch=16, col='red,)
> clipplot( points(x,y,pch=16,col='blue'), ylim=c(0,0.5) )

The last one is probably overkill, but can give a nice effect with
larger cex values.

If none of those work for you, restate the question with better detail.

Hope this helps,

-- 
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
(801) 408-8111
 
 

> -----Original Message-----
> From: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] On Behalf Of dxc13
> Sent: Wednesday, January 16, 2008 1:35 PM
> To: r-help at r-project.org
> Subject: [R] color ranges on a 2D plot
> 
> 
> useR's
> 
> I am trying to color the points on a scatter plot (code 
> below) with two colors.  Red for values 0.5 -1.0 and blue for 
> 0.0 - .49.  Does anyone know a easy way to do this?
> 
> x <- runif(100, 0, 1)
> y <- runif(100, 0, 1)
> plot(y ~ x, pch=16)
> 
> Thanks,
> dxc13
> --
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> 93457.html
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